There are several tourniquets on the market that can be used, in cases of severe limb hemorrhage, by cinching to remove slack from the tourniquet and then tightening it to apply pressure to the limb. Many tourniquets have been made as devices that require two hands to effectively apply them, making them inappropriate for self-application. A few tourniquets that are applicable with just one hand, of the type described in U.S. Pat. Nos. 7,892,253 and 7,776,064, require pulling on webbing in a direction tangential to the limb for cinching. Pulling tangentially causes the tourniquet to rotate around the limb if adequate grip or frictional force is absent, which is usually the case when only one hand is used. This proves to be a hindrance in the cinching process, making the application of the tourniquet difficult and slow.
Many tourniquets have been made as devices that can be applied only on limbs with an accessible open end. These tourniquets are in the form of closed loops and can only be slid on from an open end, making them impossible to apply on entrapped or severely mangled limbs. A few tourniquets that are applicable on such limbs, of the type described in U.S. Pat. No. 8,343,182, are in the form of open loops that may be closed during application. However, accidental opening of the loop after application is a concern with these tourniquets.
U.S. Pat. No. 6,960,223 describes a tourniquet that may be applied with one hand and without pulling tangentially relative to the tourniquet. This tourniquet consists of two concentric loops formed such that pulling on the outer cinches the inner loop. However, pulling on the outer loop also creates friction between the loops, preventing the mechanism from effectively working
U.S. Pat. No. 7,582,102 describes a tourniquet with a compliant support structure that provides friction between the limb and the device to prevent its rotation about the limb. However, this structure limits application to only limbs of certain sizes. It also adds bulk to the device making it difficult to carry. In addition, it has a tendency to severely pinch skin when applied. This can cause excessive pain and discomfort and prevent a user from adequately tightening the device, making it ineffective.
Most tourniquets produce a noticeable sound either during cinching, tightening or unpacking. Sound is particularly undesirable in military applications in hostile combat zones where it may expose the user's position.